Abstract
THE SATURNIAN SYSTEM.—Dr. W. Meyer, late Assistant Astronomer at the Observatory of Geneva, has published in t. xxix. of Mémoires de la Société de Physique et d' Histoire Naturelle de Genève a determination of the dimensions of Saturn's rings and of the orbits of six satellites, and the mass of the planet, founded upon observations made at the Observatory, with a filar-micrometer on the Merz refractor of 10 inches aperture, presented to that institution by the late Prof. Plant-amour. The observations in question were made during the opposition of 1881, and upon a system which it was believed would give the measures a superiority over those obtained with the same instrument in the previous year. The memoir on Saturn and his satellites, which has been separately published, is preceded by a very minute description of the Plantamour equatorial by Prof. Thury. The measures are printed in detail with the elements of reduction employed; they extend from August 15 to December 19. Dr. Meyer considers that Mimas was certainly observed on five nights, though he remarks: “Même dans la colossale lunette de Vienne, c'est un objet très délicat, qui est rarement visible quand il n'est pas près d'une élongation.” On November 4, at l0h. 31m., a very faint object was observed, approximately in the position—x = 254″, y = - 35″, which, by means of Prof. Asaph Hall's ephemeris, Dr. Meyer identifies as Hyperion. In the discussion of the orbits of the satellites (Enceladus, Tethys, Dione, Rhea, Titan, and Japetus) provisional elements are assumed, and are corrected in the usual manner by equations of condition. In order to determine the mean motions, the Geneva results are compared with those of Bessel in the case of Titan, while for other satellites the comparison is made with the epochs deduced by Jacob from his measures at Madras in the years 1856–58, it being considered that, in view of the precision attaching to them, little would be gained by having recourse to the older observations, especially as difficulties attend their explanation in many cases.
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Our Astronomical Column . Nature 31, 65 (1884). https://doi.org/10.1038/031065a0
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DOI: https://doi.org/10.1038/031065a0